The invention relates to work holders and, more particularly, to a truss jigging system with provisions for reducing the length of time between changing from one jig formation to another.
Home architects are always striving for new and fresh designs to appeal to the new home buyer and/or home renovator who wants something distinctive. One of the ways to provide fresh new designs is to design elaborate truss-supported structures where nearly every truss has a unique design. Hence there is pressure from the marketplace for truss jigging systems which have a very short times between changing from one jig formation to another.
It is an object of the invention to provide a fully automatic truss jigging system, wherein the time to change jig formation is as short as a minute to just a few minutes. This object of the invention is achieved by controllable drive systems that are driven from a controller and spin a belt. Albeit, it is expected that user will give the controller and manual signal to make the change of the jig formation.
It is an alternate object of the invention to provide a semi-automatic truss jigging system. This is not a backward step from the previous object of the invention. Instead, this allows for, among other things, a user to make a last second personal intervention to make fine, last-minute adjustments.
It is a further object of the invention to a truss jigging system with manual drives for changing the jig formation (eg., like a hand crank or a wrench put to service as a hand crank). And again, this object is also not a backward step from the previous two. When architects and/or builders are designing and constructing a distinctive and elaborate structure, the unexpected might happen. There might be a need to make a last truss based on measurements made by the builder in the field. The manual drive provisions might make the changeover time a lot slower than the fully automatic and semi-automatic provisions. However, when workers feel like they aren't getting exactly what they need, and to the point where they mistrust the computers, the manual speed-drive provisions restore the jig template formation fully back to humans.
These and other aspects and objects are provided according to the invention in a truss jigging system comprising the following.
There is a table forming a support plane on which work pieces are supported and extending between a front edge and a spaced-away back edge and being elongated side to side between a left side edge and a spaced-away right side edge.
The table is formed with a plurality of elongated, narrow surface slots through the support plane and extending on generally parallel axes to each other in the front to back direction, the surface slots being recessed down in the table to widen out into enlarged, tubular slideways that are spaced below the support plane and correspondingly are elongated and extend generally parallel with the same axis as the respective surface slot.
There are a plurality of locating pins, and, a plurality of carriages for not only inserting into the slideways for sliding transit therein but also for carrying one of the plurality of locating pins for sliding transit therewith while the locating pin extends through the surface slot and protrudes above the support plane.
There is furthermore a plurality of endless belts, one each for each carriage, and, a plurality of idler wheels, one each for each slideway, and each disposed proximate the front edge of table to service a respective one of the slideways, as well as, a plurality of drive wheels, one each for each slideway, and each disposed proximate the back edge of table to service a respective one of the slideways.
Wherein, each endless belt is strung around a respective one of the idler wheels and a respective one of the drive wheels to form a pair of elongated runs, one run being an elongated return run and the other run having a respective one of the carriages affixed thereto and coursing through the respective slideway that the respective two wheels service, such that, driving the drive wheel moves the locating pin back and forth along the front to back axis of the respective surface slot.
It is optional that the table defines a plurality of inverted-T shaped slots wherein the vertical parts correspond to the surface slots and horizontal parts correspond to the slideways.
The table might further comprises a pair of parallel jigging bars for each inverted-T shaped slot.
The table might moreover further comprises a support deck below the level of and for supporting the jigging bars, the support deck extending between a front edge and a spaced-away back edge and being elongated side to side between a left side edge and a spaced-away right side edge.
Preferably, the jigging bars have top surfaces level with the support plane. and
The table might correspondingly comprises a multiplicity of infill sections which are elongated between a front edge and spaced back edge and compact between spaced front and right edges, and sized for filling in between each of the plurality of pairs of jigging bars that define a respective one of the plurality of invert-T shaped slots and are supported by the support deck for presenting a work surface level with the tops of the jigging bars and level with the support plane. It is preferred then that, at least one adjacent pair of a jigging bar and infill section define a tubular conduit parallel to the horizontal part of the inverted-T shaped slot and providing a passageway for the return run of the endless belt.
It is a preferred aspect of the invention to further provide the following:—
a second plurality of plurality of locating pins;
a second plurality of carriages for not only inserting into the slideways for sliding transit therein but also for carrying one of the second plurality of locating pins for sliding transit therewith while the locating pin extends through the surface slot and protrudes above the support plane;
a second plurality of endless belts, one each for each of the second plurality of carriages;
a second plurality of idler wheels, one each for each slideway, and each disposed proximate the front edge of table to service a respective one of the slideways;
a second plurality of drive wheels, one each for each slideway, and each disposed proximate the back edge of table to service a respective one of the slideways;
wherein each of the second plurality of endless belts is strung around a respective one of the second plurality of idler wheels and a respective one of the second plurality of drive wheels to form a pair of elongated runs, one run being an elongated return run and the other run having a respective one of the second plurality of carriages affixed thereto and coursing through the respective slideway that the respective two wheels service such that, driving the drive wheel moves the locating pin back and forth along the front to back axis of the respective surface slot; and
wherein each slideway services two carriages, one of the first plurality and one of the second plurality, which cannot pass each other but can be driven independently.
The table might further defines a pair of tubular conduits flanking each slideway, one providing a passageway for the return run of the respective one of the first plurality of endless belts and the other providing a passageway for the return run of the respective one of the second plurality of endless belts.
It is preferred to provide a plurality of drive motors, one each for driving a respective one of the plurality of drive wheels, as well as, a control system for controlling the plurality of drive motors.
It is furthermore preferred if the idler wheels are mounted to the table flush below the support plane so that, other than the locating pins and work pieces, the airspace above support plane proximate the front edge of the table is otherwise clear.
The plurality of drive motors may be mounted to the table along the back edge such that the project above the support plane.
For maintenance and adjustment purposes, it is preferred to provide a plurality of belt tensioning systems, one each for a respective one of each of the plurality of belt. Each belt tensioning system might be implemented in the form of comprising a horizontally-adjustable mounting provision that is adjustable back and forth in the front to back direction and provides a mounting provision for one of the drive or idler wheels.
The endless belt can be reckoned as ‘endless’ in several different ways. One way includes the following. That is, each endless belt includes the respective carriage affixed thereto whereby the carriage forms a splice between opposed tag ends of the belt.
This application is commonly-invented, commonly-owned with U.S. Pat. No. 5,048,409, entitled Truss Fabrication Machine with Joystick Controls, and U.S. Pat. No. 6,318,251, entitled Automatic Control System for a Truss Fabricating Machine, the disclosures of which are incorporated herein by this reference thereto.
A number of additional features and objects will be apparent in connection with the following discussion of the preferred embodiments and examples with reference to the drawings.